The Work Breakdown Structure $($WBS$)$ is a view into the project which shows what work the project encompasses. It is a tool that helps to easily communicate the work and processes involved to execute the project. The Project Manager and project team use the WBS to develop the project schedule, resource requirements, and costs.

Levels of the Work Breakdown Structure

Level $0=$ Project deliverable $$ Overall project to be delivered.

Level $1=$ Key Deliverables $$ Deliverables required for the success of the project based on the scope.

Level $2=$ Sub$-$deliverables $$ Sub$-$deliverables are the components that make up the key deliverables. Sub$-$deliverables require that the work package get completed. Sometimes, the work package is established at this level.

Level $3=$ Work Package $$ The task level of the WBS where cost and resources and be assigned. Task must begin with a verb. The Work Package rolls up to the sub$-$deliverables.